A search for images of a pop-up with cargo showed a whole bunch.
For now, I'll think I'll stick to the utility trailer conversions.
The smallest RV style toy haulers seem built for bicycles or other lightweight toys. The pop ups need set up time.
I'm going to try to think up a way to put the cargo space over the axle(s).
Those giant cargo planes where the nose or tail swings away come to mind.
It's going to depend on the size of the trailer and the payload remaining after amenities are added. And then there's the tow package question. I wish it just said Tow Package on the window sticker, but it was a bargain sale and I didn't ask a lot of questions.